The subject matter described herein relates to acoustic transducers, such as ultrasound transducers.
Known ultrasound transducers are designed to transmit acoustic waves toward an object to be imaged and to receive reflections of the waves off of the body as acoustic echoes. These echoes are converted into an electric signal that can be used to create an image of the body. The transducers may include piezoelectric materials that are excited by an electric charge and, as a result, generate the acoustic wave. The transducers are designed to transmit most of the energy of the acoustic wave in a forward direction, such as the front side of an ultrasound transducer probe. The piezoelectric materials also generate an electric charge or signal when the materials receive the echoes. The charge or signal then may be used to generate the image.
Some energy created by the transducers may be transmitted in an opposite direction. For example, some of the energy can be transmitted as backward directed acoustic waves. These acoustic waves can be directed into the ultrasound probe. The backward directed acoustic waves may be reflected off of the housing or other structures in the ultrasound probe. The reflection of the backward directed acoustic waves may cause specular or backscattered energy or components of the acoustic waves to be directed back into the piezoelectric materials of the transducers. The receipt of the specular or backscattered energy can create visible artifacts in the image and thereby degrade the quality of the image.
In order to reduce the reflection of the backward directed acoustic waves, some known transducers include backing layers that attenuate the acoustic waves. These backing layers tend to be poor thermal conductors, which can cause a considerable amount of thermal energy being created during use of the ultrasound transducers. This thermal energy can be trapped inside the ultrasound probe between the piezoelectric materials and the probe housing. The thermal energy can significantly heat the piezoelectric materials and other components within the probe, which can damage the internal components of the probe and/or degrade the quality of image, or be a safety issue.